I am going to rebuild my 2.8 into a 3.1, (I want to keep the car looking stock so a motor swap is out) meaning that the bore is going to be 3.5 (also bored 0.030 over) and the stroke is going to be 3.31. I am going to use 3.1 pistons and a 3.1 crank. My question is do any of you foresee any problems in the future? Will the crank fit? I have heard that the 2.8 and 3.1 were the same block. Will the computer for the 2.8 work on the 3.1? Any advice or suggestions? What is going to happen if I use the same computer and any advantages to getting a 3.1 computer because I know the 3.1 had a knock sensor and they are speed density and not Mass air flow ( from what I have read ) Also the compression of a 2.8 is 8.9:1 and a 3.1 is 8.5:1. What would the compression be for this motor using the same heads? Thanks

-William

 

that seems like alot of work, 3.1's were stock in later birds, so your car will look stock, it seems like a clean swap would be the best idea. don't know answers to your other questions. sorry

 

Why rebuild, drop a used 3.4l block underneither your intake. Use the search button up top, and find TONS of answers, then a few of us on here can guide you on questions you have after that.

KED85 is the father of this swap, project85, myself, and a few others have done this swap.

a 3.1l crank, with a .030 bore over is 3.2/3.3, not 3.5.

Save yourself some labor, and money (unless you have a 3.1 laying around that you got for free) and buy a 3.4l.

Computer/sensors will not know the difference, you will only need the injectors from 3.1l (for 3.1) or 3.4l injectors, (for a 3.4)